So if TV advertising is currently the biggest loser, does that mean YouTube, the king of Web video, could be the clear winner?

Several advertisers and analysts say that YouTube has become a viable alternative to TV in the minds of top brands, whose ad budgets have typically been focused on TV.

That doesn’t mean that everyone is sold on the idea of Web video warranting a sales market centered on long-term ad commitments like the TV upfront.

Google, and 3o-plus other Web video outlets have hosted “NewFronts” sales events each spring for the past couple of years, just prior to the TV upfront sales season–as they all aspire to snatch away a portion of the $70 billion that is spent annually on TV advertising. (Web video advertising, while expected to grow at a 30% clip this year, is just a $7.7 billion market, says eMarketer).

With Google Preferred, YouTube has perhaps been the most aggressive in trying to create an urgent, TV-like ad market designed to sell a finite amount of ad space. Essentially, YouTube sets aside its most desirable video content, makes it available for marketers to sponsor, and if they don’t buy in quickly, they’ll get shut out–or at least, that’s the dynamic YouTube is looking to create.

Last year, Google said that Preferred sold out. A few weeks ago, the company talked up this year’s effort on its earnings call, boasting that demand was three times higher compared to the same period last year, when Google Preferred was new in the market.

“We are organized around buying premium video, and Google Preferred has now moved into that category with Hulu and full-episode TV content,” said John Swift, Omnicom Media Group’s chief executive of North American investment. “There has been an increase in client demand.”

For a while, advertisers’ favorite place to spend TV dollars online was on TV shows streamed on the Web on either TV networks’ sites and apps or on Hulu. Meanwhile, YouTube long carried the reputation as mostly housing low-quality home videos.

Brands still like advertising in TV shows online, but as Mr. Swift noted, YouTube has done a good job of communicating the value of its own stars and helping brands find them.

Plus, YouTube has come a long way in catering to marketers’ desires to track ads on the site like TV ads, such as incorporating Nielsen data and offering advertisers guarantees on how many people ad campaigns will reach, much like TV does, said Eric Johnson, president of the digital agency Ignited. “The product they are offering is measurable, and clients are comfortable.”

And clients like the fact that they only pay for ads on YouTube that people don’t skip. “There is a growing recognition in the industry of the power of getting people to choose to consume your ad,” Mr. Johnson said. As opposed to TV ads, which generally interrupt people’s viewing experiences.

Tara Walpert Levy, who runs YouTube’s agency business in the U.S., said that the company is “close to finished” in selling Google Preferred ads this year. Last year, YouTube inked Preferred deals with 100 or so brands, 30 of which were new to YouTube.

While she declined to provide specific figures, she said many of those brands are upping their commitments this time around. “This year, we found that we were selling right alongside TV [in the upfronts],” she said. “That was distinctively different than years prior. We think it reinforces the advertiser perception that YouTube has become a true television-comparable alternative.”

Of course, not everyone agrees with that assessment. One ad buyer said that YouTube was looking for double-digit percentage price increases for Preferred this year, which wasn’t going over well with some clients, especially when there are alternative ways to buy ads on YouTube, such as via automated digital tools and multichannel networks like Maker Studios.

Pivotal Research analyst Brian Wieser said that for most top advertisers, YouTube is not yet perceived as being on the same level as TV. “At the right price, YouTube is an effective complement to TV,” he said. “But the relative appeal of YouTube versus [relatively low priced] cable ads is pretty low.”

That’s because, according to Mr. Wieser, advertising on mid-level cable networks generally provides a brand-safe environment and can deliver a national audience in short bursts of time, which is important for advertisers with timely messages.

And some cable networks can offer rates that are in the neighborhood of $10 per-one thousand viewers reached. Prices for YouTube range widely, but can be much higher for Google Preferred, he said.

YouTube gaining legitimacy in the minds of more advertisers is one thing. That doesn’t mean every advertisers wants to buy ads on YouTube like they have on TV in the past. One ad buyer noted that in a climate where many marketers say they are pulling back on upfront TV deals because of a push for more spending flexibility, there is little desire or need to commit to long term deals with YouTube, or any other Web video outlet.

Today, “flexibility is as important as pricing,” said Amanda Richman, president of investment and activation at the media buying firm Starcom. “And I don’t get the sense that anyone is saying that this is a must buy. There are no must buys in media anymore.”

And what about Facebook? Isn’t the social network’s eye-popping ascendance in Web video making them a serious contender for ad budgets? Not this year, said Ms. Richman and several other ad buyers, as Facebook is still figuring out its video ad offerings. Facebook generally doesn’t sell ads alongside specific content, for example, though it does offer brands a huge audience and sophisticated targeting options.

But interestingly, a number of agencies and marketing executives say that Facebook and YouTube are helping create a new breed of advertisers–brands which rarely can ever afford to advertise on TV but can use the size of Facebook and Google to execute TV-like video campaigns. Call them “TV nevers.”

“There is a lot of money shifting from TV to Web video, and it is for us mainly YouTube and Facebook,” said Hermann Hassenstein, global head of marketing planning at Puma.

Ignited’s Mr. Johnson said he is seeing more brands start with video ads on YouTube, and increasingly Facebook, rather than moving from TV.

“With some smaller budget clients, we are on the cusp of that, where they are saying, ‘we can’t afford TV, but you can get the TV-like effect.’ You can produce a video ad that looks like a sexy commercial, but you are primarily doing it on Facebook and YouTube,” he said.

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